Slow on the uptake?

Or it's a matter of the eye of the beholder. That ruddy golf-ball, (I think "they" say it's unobtrusive) is clearly visible from our front garden ("Yard" the them furriners) at 20km/12.5mls distance. And, according to my best guesstimate in G© maps must be visible from around twice that, from certain points.
What just dawned on me is the fact that the "East fell side" to us is, actually, the West side of the Pennines.